Manufacture of wrought iron from bessemer steel



Patented Aug. 25, 1931 UNITED STATES PATENT OFFICE JAMES ASTON ANDADDISON H. BEALE, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOBS,

BY MESN E ASSIONMENTS, TO A. M. BYERS COMPANY, OF PITTSBURGH, PENNSYL-VANLA, A CORPORATION OF PENNSYLVANIA MANUFACTURE OF WROUGHT No Drawing.Application filed July 19,

Our invention relates to the Aston process of making wrought iron, such,for example, as set forth in several United States patents of JamesAston, such as N 0. 1,370,507, granted March 8, 1920, for Method ofmaking wrought iron pipe; No. 1,412,823, granted April 18, 1922, forMethod of making wrought iron; and No. 1,469,373, granted October 2,1923, for Manufacture of wrought lI'OIl- Our invention relates to themanufacture of wrought iron in accordance with the Aston process fromBessemer converter metal. It has been found in practice that the use ofthe Bessemer converter has certain advantages over the use of openhearth steel or electric steel. After considerable experimenting withBessemer metal in the Aston process, we have discovered that the qualityof the wrought iron ball produced in the Aston process is improved, anda better reaction obtained between the poured-in steel and the puddleslag when the converter heat is full blownthat is, when the carbon isreduced to below .10%. In practice we preferably blow the heat down toabout 06%, which, in general steel practice, is termed a full orover-blown heat.

In Bessemer practice, it is well known that if such a heat werecastdirectly into ingots the product would be red short and would crackin working the same. For this reason, in Bessemer steel practice,deoxidizing agents, such as manganese, silicon and aluminum, are added.these elements, or combinations of them with similar elements. combiningwith the oxygen in the material to deoxidize and degasifv the same.

We have discovered that in the Aston process when Bcssemerized metalwhich is blown to such an extent that the carbon is below 10%, andpreferably about 06%, is used, the oxidized condition of the steel,which would produce red shortness in the final ma- 45 terial. isovercome by the deoxidizing and dcgasifyin action of the bath of puddleslag into which the metal is poured for shotting. A reaction takes placebetween the blown metal and the iron oxide slag which causes deoxidationand degasification of the metal IRON FROM BESSEMER STEEL 1928. SerialNo. 294,049.

during the shotting rocess in the slag. Consequently, the materialrolled from the resulting ball formed in the lower part of the slagreceptacle possesses the highest qualities of genuine hand puddled iron.

On the other hand, we have found that a heat that was blown young sothat it con tained above about .10% carbon, produced, when shotted inthe same manner, a red short iron. We have also found that if the slagcontains too high a percentage of silica, the full blown metal does notlose its red-shortness, and during the rolling process works in themanner of what the puddlers term dry iron. That is. it does not have thedesired welding qualities.

In practice we have found that in order to get a high quality of wroughtiron ball, the content of silica in the slag should be less than about15% and preferably not materially above 10%. Examples of such slagswhich we have used are as follows:

Emampfe I .-A slag containing about 68.47% FeO, about 12.20% of Fe O andabout 9.92% of SiO Eammple H.-A slag containing 72.13% of FeO, 7.26% ofFe o and 10.56% of SiO;.

E ammple l I I.A slag containing about Example [.A slag containing about10.18% of SiO,.

These slags usually contain a small ercentage of phosphoricacid,manganousox1des, alumina. and magnesia, but the essentialconstituents are those of the silica. and iron oxides.

This process obviates the need of expensive and troublesome deoxidizersand degasitiers, makes the process capable of great regularity, andimproves the product. The carrying out of the Bessemer operation to apoint where the carbon is below 10% and down to a point of about 06%, iscomparatively easy, and heat after heat may be made with greatregularity. On the other hand, when carbon is present in largerpercentages. we have found that it is liable to segregate and beun-uniformly distributed in the puddle ball. causing hard spots andfailures in the finished product.

We have also found in the experimental development, that the content ofcarbon and silicon combined in the steel when ready for pouring shouldbe less than 20%, as this aids in reducing or substantially eliminatinred shortness in the wrought iron produce The silicon should at least bebelow .09% in the metal to be shotted, and is preferably far below this.High silicon in steel tends to make the material too dry and tointerfere with the proper formation of the wrought iron ball.

We have also found in this connection that the percentage of ox gen inthe steel as poured should be less tlian about .31%, while the carbonand silicon together are less than 20%. In such case we have found thatthe addition of a deoxidizing metalloid or metalloids is unnecessary,although of course some small additions may be made, especially if themetal is too wild? for proper pouring, in order to partially kilPthemetal and brin it into better pouring condition for the shottingoperation. In any case, if such metalloid additions are made to thesteel before pouring, they should not raise the combined content ofcarbon and silicon to over 20%. The manganese percentage should also berelatively low. All of these features, discovered durin the experimentaland development eri have been found to be of advantage in obtaining theproper quality and uniformity of product.

The advantages of our invention result from the discover that the carbonshould be blown to a point below 10% and preferably down to about 06%,and that when this is done deoxidizers are unnecessary, since the actionof a proper puddle slag with the desirable percentage of iron oxides,such as present in good puddle slag, will give an excellent product.

The slag should contain not over about 15% of silica, and preferably notmaterially above 10%, to give the best product. Additions may be made tothe blown metal, although this is not necessary.

Changes may be made in the Bessemer converter used, the metal may beside blown or bottom blown, although we prefer the bottom blow, andother variations may be made without departing from our invention.

We claim:

1. In the manufacture of wrought iron, the steps consisting ofBessemerizing metal until the carbon is below .10%, and then shottingthe same in a bah of iron silicate puddle slag and forming a weldedpuddle-ball therein.

2. In the manufacture of wrought iron, the steps consisting of blowingmetal to a full blow, and then pouring the same into a bath of ironsilicate puddle slag shotting the metal therein and forming a weldedpuddle-ball in the bath.

3. In the manufacture of wrought iron,

the ste s consisting of blowing ferrous metal until t e carbon contentis about 06%, and then pourin the same into and shotting it in a. bath 0iron silicate slag and thereby deoxidizing and degasifying the same, and{)OILllIlg a welded ball at the bottom of the 4. In the manufacture ofwrought iron, the steps consisting of blowing a heat of steel to a fullblow, and then,without substantial additions, pouring the same into abath of iron silicate slag and thereby deoxidizing and degasifyin thesame, and forming a welded puddleall therein.

5. In the manufacture of wrought iron, the ste 5 consisting ofBessemerizing metal until t e carbon is below .10%, and then pouring thesame into a bath of iron silicate slag having a silica content of notover about 15%, and forming a welded puddle-ball therein.

6. In the manufacture of wrought iron, the steps consisting ofBessemerizing metal until the carbon is below 10%, and then pouring thesame into a bath of iron silicate slag having a silica content notmaterially over about 10%, and forming a welded puddle-ball therein.

7. In the manufacture of wrought iron, the steps consisting ofgranulating a molten steel product wherein carbon and silicon takentogether amount to less than about 20%, and mixing the same with a slagof (paddling characteristics and forming a welde puddleball therewith.

8. In the manufacture of wrought iron, the steps consisting of forming asteel product by the Bessemer process wherein the carbon and silicontaken together are less than about 20%, granulating the same, and mixingthe granules while retaining at least a part of their original heat witha slag of puddling characteristics.

9. In the manufacture of wrought iron, the steps consisting of producinga molten steel product containing carbon and silicon which, together.amount to less than about 20%, pouring the same into a sla bath ofpuddling characteristics, and granu ating the same therein.

10. In the manufacture of wrought iron, the steps consisting of forminga steel product wherein the carbon and silicon taken together are'lessthan 20%, and pouring said steel product while molten into a slag bathof paddling characteristics to granulate it therein.

11. In the manufacture of wrought iron, the steps consisting ofBessemerizing molten iron, forming a molten steel product wherein thecarbon and silicon taken together are less than 20%, and the oxygencontent is less than 31%, granulating the same, and mixing thegranulated product with a slag of paddling characteristics.

12. In the manufacture of wrought iron, the steps consisting ofBessemerizing molten iron, forming a molten steel product wherein thecarbon and silicon taken together are less than 20%, and the oxygencontent is less than 31%, and pouring the same while molten into a slagbath of puddling characteristics.

13. In the manufacture of wrought iron, the steps consisting of forminga steel product with an oxygen content below about .31%, pouring thesame into a slag bath of iron silicate character containing iron oxides,and absorbin the oxides from the metal into the slag as t e comminutedor granulated metal descends through said slag.

14. In the manufacture of wrought iron, the steps consisting of forminga steel product containing carbon and silicon which together amount toless than 20%, and with an oxygen content below about .31%, pouring thesame into a slag bath of iron silicate character containing iron oxides,and absorb ing the oxides from the metal into the slag as the comminutedor granulated metal descends through the slag.

15. In the manufacture of wrought iron, the steps consisting ofBessemerizing metal until the carbon is about 116% and the silicon isless than 09%, pouring the molten steel product into a bath of ironsilicate slag, granulating the same therein and forming a weldedpuddle-ball in the lower part of the bath.

16. In the manufacture of wrought iron, the step comprising pouring theproduct of a steel making operation into a molten bath of iron silicateslag having a silica content of not over about 13%.

In testimony whereof we have hereunto set our hands.

JAMES ASTON. ADDISON H. BEALE.

12. In the manufacture of wrought iron, the steps consisting ofBessemerizing molten iron, forming a molten steel product wherein thecarbon and silicon taken together are less than 20%, and the oxygencontent is less than 31%, and pouring the same while molten into a slagbath of paddling characteristics.

13. In the manufacture of wrought iron, the steps consisting of forminga steel product with an oxygen content below about 31%, pouring the sameinto a slag bath of iron silicate character containing iron oxides, andabsorbin the oxides from the metal into the slag as t e comminuted orgranulated metal descends through said slag.

14. In the manufacture of wrought iron, the steps consisting of forminga steel product containing carbon and silicon which together amount toless than 20%, and with an oxygen content below about 31%, pouring thesame into a slag bath of iron silicate character containing iron oxides,and absorbing the oxides from the metal into the slag as the comminutedor granulated metal descends through the slag.

15. In the manufacture of wrought iron, the steps consisting ofBessemerizing metal until the carbon is about .06% and the silicon isless than .09%, pouring the molten steel product into a bath of ironsilicate slag, granulating the same therein and forming a weldedpuddle-ball in the lower part of the bath.

16. In the manufacture of wrought iron, the step comprising pouring theproduct of a steel making operation into a molten bath of iron silicateslag having a silica content of not over about 13%.

In testimony whereof we have hereunto set our hands.

JAMES ASTON. ADDISON H. BEALE.

Certificate of Correction Granted August 25, 1931, to JAMES AsroN ET AL.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Pa e 1,lines 79 and 80, strike out Patent No. 1,820,177.

Example I.--A slag containing about 10.18% of e110,. and insert instead723.30%

of F to 1020% of Fe Q and about 10.18% a 850 and that the said LettersPatent should be read with these corrections t erein that the same mayconform to the record of the case in the Patent Oflice.

Signed and sealed this 22nd day of September, A. D. 1931.

[smut] M. J. MOORE, Acting G'anwtisu'omr of Patents.

Certificate of Correction 7 Patent No. 1,820,177. Granted August 25,1931, to JALEES ASTON ET AL. It is hereby certified that error a pearsin the printed specification of the above numbered patent requiringcorrectlon as follows: Page 1, lines 79 and 80, strike out Ewwmple l.-Aslag containing about 10.18% of SiOg. and insert instead 72.30% of F80to 10.20% of F13 0, and about 10.18% of 850 and that the said LettersPatent should be read with these corrections therein that the same mayconform to the record of the case in the Patent Ofiice.

Signed and sealed this 22nd day of September, A. D. 1931.

1 M. J. MOORE,

Acting Gomamlssiomr of Patents.

